GIS (Geographical Information Systems) software is used to create, manage and visualize geographically referenced data. Such software can be used in location determination applications, meteorological applications, geographic/geological applications and the like. The geographical entities that are dealt with are modeled as geometric figures and calculations are generated based on such geometric figures. For example, landforms such as counties, states, countries and the like can be modeled in the GIS software as areal figures such as polygons which enclose a certain area within their vertices. Some landforms can also be modeled as polygons with holes. Similarly, other geographical entities such as particular locations, rivers or geographic/political borders and the like can be modeled as non-areal geometric shapes such as points, lines or collections thereof.